The patch titled
Subject: m68k: allow pte_offset_map[_lock]() to fail
has been added to the -mm mm-unstable branch. Its filename is
m68k-allow-pte_offset_map-to-fail.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/m68k-allow-pte_offset_map-to-fail.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Hugh Dickins <hughd@xxxxxxxxxx>
Subject: m68k: allow pte_offset_map[_lock]() to fail
Date: Thu, 8 Jun 2023 12:15:16 -0700 (PDT)
In rare transient cases, not yet made possible, pte_offset_map() and
pte_offset_map_lock() may not find a page table: handle appropriately.
Restructure cf_tlb_miss() with a pte_unmap() (previously omitted)
at label out, followed by one local_irq_restore() for all.
Link: https://lkml.kernel.org/r/795f6a7-bcca-cdf-ad2a-fbdaa232998c@xxxxxxxxxx
Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Alexander Gordeev <agordeev@xxxxxxxxxxxxx>
Cc: Alexandre Ghiti <alexghiti@xxxxxxxxxxxx>
Cc: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Christian Borntraeger <borntraeger@xxxxxxxxxxxxx>
Cc: Chris Zankel <chris@xxxxxxxxxx>
Cc: Claudio Imbrenda <imbrenda@xxxxxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Cc: Greg Ungerer <gerg@xxxxxxxxxxxxxx>
Cc: Heiko Carstens <hca@xxxxxxxxxxxxx>
Cc: Helge Deller <deller@xxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: John David Anglin <dave.anglin@xxxxxxxx>
Cc: John Paul Adrian Glaubitz <glaubitz@xxxxxxxxxxxxxxxxxxx>
Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: Max Filippov <jcmvbkbc@xxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: Michal Simek <monstr@xxxxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: Mike Rapoport (IBM) <rppt@xxxxxxxxxx>
Cc: Palmer Dabbelt <palmer@xxxxxxxxxxx>
Cc: Palmer Dabbelt <palmer@xxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx>
Cc: Russell King <linux@xxxxxxxxxxxxxxx>
Cc: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Cc: Thomas Bogendoerfer <tsbogend@xxxxxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/m68k/include/asm/mmu_context.h | 6 ++-
arch/m68k/kernel/sys_m68k.c | 2 +
arch/m68k/mm/mcfmmu.c | 52 ++++++++++----------------
3 files changed, 27 insertions(+), 33 deletions(-)
--- a/arch/m68k/include/asm/mmu_context.h~m68k-allow-pte_offset_map-to-fail
+++ a/arch/m68k/include/asm/mmu_context.h
@@ -99,7 +99,7 @@ static inline void load_ksp_mmu(struct t
p4d_t *p4d;
pud_t *pud;
pmd_t *pmd;
- pte_t *pte;
+ pte_t *pte = NULL;
unsigned long mmuar;
local_irq_save(flags);
@@ -139,7 +139,7 @@ static inline void load_ksp_mmu(struct t
pte = (mmuar >= PAGE_OFFSET) ? pte_offset_kernel(pmd, mmuar)
: pte_offset_map(pmd, mmuar);
- if (pte_none(*pte) || !pte_present(*pte))
+ if (!pte || pte_none(*pte) || !pte_present(*pte))
goto bug;
set_pte(pte, pte_mkyoung(*pte));
@@ -161,6 +161,8 @@ static inline void load_ksp_mmu(struct t
bug:
pr_info("ksp load failed: mm=0x%p ksp=0x08%lx\n", mm, mmuar);
end:
+ if (pte && mmuar < PAGE_OFFSET)
+ pte_unmap(pte);
local_irq_restore(flags);
}
--- a/arch/m68k/kernel/sys_m68k.c~m68k-allow-pte_offset_map-to-fail
+++ a/arch/m68k/kernel/sys_m68k.c
@@ -488,6 +488,8 @@ sys_atomic_cmpxchg_32(unsigned long newv
if (!pmd_present(*pmd))
goto bad_access;
pte = pte_offset_map_lock(mm, pmd, (unsigned long)mem, &ptl);
+ if (!pte)
+ goto bad_access;
if (!pte_present(*pte) || !pte_dirty(*pte)
|| !pte_write(*pte)) {
pte_unmap_unlock(pte, ptl);
--- a/arch/m68k/mm/mcfmmu.c~m68k-allow-pte_offset_map-to-fail
+++ a/arch/m68k/mm/mcfmmu.c
@@ -91,7 +91,8 @@ int cf_tlb_miss(struct pt_regs *regs, in
p4d_t *p4d;
pud_t *pud;
pmd_t *pmd;
- pte_t *pte;
+ pte_t *pte = NULL;
+ int ret = -1;
int asid;
local_irq_save(flags);
@@ -100,47 +101,33 @@ int cf_tlb_miss(struct pt_regs *regs, in
regs->pc + (extension_word * sizeof(long));
mm = (!user_mode(regs) && KMAPAREA(mmuar)) ? &init_mm : current->mm;
- if (!mm) {
- local_irq_restore(flags);
- return -1;
- }
+ if (!mm)
+ goto out;
pgd = pgd_offset(mm, mmuar);
- if (pgd_none(*pgd)) {
- local_irq_restore(flags);
- return -1;
- }
+ if (pgd_none(*pgd))
+ goto out;
p4d = p4d_offset(pgd, mmuar);
- if (p4d_none(*p4d)) {
- local_irq_restore(flags);
- return -1;
- }
+ if (p4d_none(*p4d))
+ goto out;
pud = pud_offset(p4d, mmuar);
- if (pud_none(*pud)) {
- local_irq_restore(flags);
- return -1;
- }
+ if (pud_none(*pud))
+ goto out;
pmd = pmd_offset(pud, mmuar);
- if (pmd_none(*pmd)) {
- local_irq_restore(flags);
- return -1;
- }
+ if (pmd_none(*pmd))
+ goto out;
pte = (KMAPAREA(mmuar)) ? pte_offset_kernel(pmd, mmuar)
: pte_offset_map(pmd, mmuar);
- if (pte_none(*pte) || !pte_present(*pte)) {
- local_irq_restore(flags);
- return -1;
- }
+ if (!pte || pte_none(*pte) || !pte_present(*pte))
+ goto out;
if (write) {
- if (!pte_write(*pte)) {
- local_irq_restore(flags);
- return -1;
- }
+ if (!pte_write(*pte))
+ goto out;
set_pte(pte, pte_mkdirty(*pte));
}
@@ -161,9 +148,12 @@ int cf_tlb_miss(struct pt_regs *regs, in
mmu_write(MMUOR, MMUOR_ACC | MMUOR_UAA);
else
mmu_write(MMUOR, MMUOR_ITLB | MMUOR_ACC | MMUOR_UAA);
-
+ ret = 0;
+out:
+ if (pte && !KMAPAREA(mmuar))
+ pte_unmap(pte);
local_irq_restore(flags);
- return 0;
+ return ret;
}
void __init cf_bootmem_alloc(void)
_
Patches currently in -mm which might be from hughd@xxxxxxxxxx are
arm-allow-pte_offset_map-to-fail.patch
arm64-allow-pte_offset_map-to-fail.patch
arm64-hugetlb-pte_alloc_huge-pte_offset_huge.patch
ia64-hugetlb-pte_alloc_huge-pte_offset_huge.patch
m68k-allow-pte_offset_map-to-fail.patch
microblaze-allow-pte_offset_map-to-fail.patch
mips-update_mmu_cache-can-replace-__update_tlb.patch
parisc-add-pte_unmap-to-balance-get_ptep.patch
parisc-unmap_uncached_pte-use-pte_offset_kernel.patch
parisc-hugetlb-pte_alloc_huge-pte_offset_huge.patch
powerpc-kvmppc_unmap_free_pmd-pte_offset_kernel.patch
powerpc-allow-pte_offset_map-to-fail.patch
powerpc-hugetlb-pte_alloc_huge.patch
riscv-hugetlb-pte_alloc_huge-pte_offset_huge.patch
s390-allow-pte_offset_map_lock-to-fail.patch
s390-gmap-use-pte_unmap_unlock-not-spin_unlock.patch
sh-hugetlb-pte_alloc_huge-pte_offset_huge.patch
sparc-hugetlb-pte_alloc_huge-pte_offset_huge.patch
sparc-allow-pte_offset_map-to-fail.patch
sparc-iounit-and-iommu-use-pte_offset_kernel.patch
x86-allow-get_locked_pte-to-fail.patch
x86-sme_populate_pgd-use-pte_offset_kernel.patch
xtensa-add-pte_unmap-to-balance-pte_offset_map.patch
